In many industrial applications, free-flowing materials (fluids) are delivered with the aid of fluid delivery devices and placed or dispensed onto substrates. The fluids may be adhesives, paints, sealing materials or gases, for example, and the substrates may be sanitary articles, plastic films, furniture or machine parts and the like. Depending on the specific application, the fluids may be delivered in the form of beads, strips or films, for example, or the material may be sprayed, if necessary, with the aid of a gaseous stream that influences the fluid. The fluid delivery devices are connected to a fluid source, for example a container for adhesives, and the fluid is transported with the aid of a pump to a discharge opening that is circular or slot-shaped, for example.
In some applications, it is advantageous or necessary that the fluid be heated before it is delivered. In the case of spraying methods, it may be advantageous to heat a gas that affects a liquid to be delivered. In many applications, it may be necessary to heat a liquid to be delivered, in particular a fluid hot-melt adhesive prior to delivery and application to a substrate or material. A fluid delivery device with an integrated heat transfer chamber is known from the applicant's patent EP 1 419 826 A2, for example, in which it was proposed that a structure with cavities, made in particular of a sintering material, be disposed in a heat transfer chamber in order to influence the transfer of heat in an advantageous manner.
There is a need for further improvement of fluid delivery devices which have a heat transfer member. There is therefore a need to optimize the fluid mechanics of heat transfer member for heating or also for cooling a fluid, so that they can be better adapted to changing viscosities of the fluid, for example. There is also a need to reduce the geometrical dimensions of the fluid delivery device as a whole. In many cases, it is also necessary to process and apply temperature-sensitive fluids, particularly hot-melt adhesives or thermoplastic materials which must be gently heated, without causing temporary local overheating and hence detrimental impacts on the properties of the material.
The object of the present invention is to specify a device and a method for delivering a fluid, and a heat transfer member for a fluid delivery device, which take up relatively little installation space and/or which are suitable for processing temperature-sensitive fluids, particularly hot-melt adhesives, and/or are fluidically optimized, especially with regard to changing viscosities of the fluids.